Grantee Research Project Results

 

Isolated micro-hydroelectric mini-grids provide renewable electricity to thousands of small villages throughout the world. These distributed generation systems enable the use of electric lighting and cooking appliances, allowing residents to switch from using kerosene lanterns and wood-fired stoves, thereby reducing carbon dioxide (CO2) emissions and drastically improving indoor air quality (Dorji 2007, Smith 1995). Unfortunately, due to the limited nature of the electricity supplied by these small systems, mini-grids often face a “tragedy of the commons”: brownouts that frequently occur in the mornings and evenings during periods of peak demand (Figure 1) (Dorji 2007). The lowered voltage that characterizes a brownout causes lights to dim, televisions to flicker and electrical appliances not to work properly. These technical failings result in residents switching back to fuel-based cooking methods and losing confidence in the reliability of the electricity service.

 

Figure 1. Voltage and current on one phase of load output at the powerhouse in Rukubji, Bhutan on July 19th, 2010.
The periodic increases in current and corresponding decreases in voltage represnt the morning and evening brownouts
that are characteristic of micro-hydrielectric mini-grids in Bhutan and elsewhere around the world (L). Typical
cooking appliances in Rukubji, Bhutan include water boilers, rice cookers, curry cookers and LPG stoves (R).¹

 

In Bhutan and many other countries, brownouts have been linked to the use of electric cooking appliances such as rice cookers and water boilers (Figure 1). In his research on micro-hydroelectric mini-grids in Bhutan, Karma P. Dorji suggested that brownouts could be mitigated by distributing the use of these appliances more evenly throughout the day (Dorji 2007). For example, rice cookers often draw 600-1,000 watts when cooking the rice, but less than 100 watts to keep it warm. Therefore rice that is cooked near mid-day can be kept warm until the evening meal without requiring high levels of electricity use during the peak periods. Encouraging this sort of load shifting can increase the quality of electricity delivered without an increase in the generation capacity of the system, eliminating the need for diesel backup generators or potentially hazardous and expensive battery banks.

 

 

In addition to the project’s benefits to people and the planet, the P3 GridShare project offers educational opportunities on many levels. Our Phase II proposal involves students and faculty, the Bhutan Power Corporation (BPC), Bhutan's Department of Energy (DOE), and villagers of Rukubji. All participants involved will expand their understanding of brownouts associated with micro-hydro systems in Bhutan, the implications of the brownouts, and potential solutions to the brownout problem. Inherently as a student research project, all of the students involved throughout the process have gained a first-hand education in circuit design, low-cost manufacturing, grant writing, data analysis, development of educational materials and international project coordination. Additionally, the design and manufacture of the GridShare device has served as a thesis project for a student completing his Master’s in Environmental Resources Engineering (Quetchenbach, 2011), while analysis regarding performance of the devices and the acceptance of the community will serve as a separate thesis for a student in the Energy, Environment and Society Master’s program. Students involved in the project have presented on numerous occasions to clubs, classes and organizations to encourage other students to pursue similar projects.

 

Beyond the educational opportunities for students at HSU, the GridShare project has served as an educational tool for engineers working with the Bhutan Power Corporation who have learned about brownout issues and survey techniques, as well as new technologies for data collection and analysis. Additionally, the villagers of Rukubji, Bhutan will have a greater understanding of their electrical system and their ability to manage the system in part. As part of the comprehensive education, the GridShare team presented concepts of microhydro generation and load shifting to students in grades 4, 5 and 6 at the local primary school (Figure 2). A serendipitous meeting enabled the team to spend an afternoon as guest presenters for a group of Bhutanese and American high school students studying energy use as they pedaled across Bhutan on the Bhutan Foundation’s Ride for Climate (http://bhutanrideforclimate.org/).

 

Figure 2. Chhimi Dorji asks students "where their electricity comes from?" and describes microhydro
system (L). Meg Harper and Nathan Chase help students understand the concept of load shifting (R).

 

 

The purpose of this project is to develop a “GridShare” device that uses smart grid technology to encourage load shifting. Changing the time of use of high power appliances can reduce the severity of brownouts on power-limited mini-grids, potentially increasing the utility of renewable energy mini-grids worldwide.

 

In Phase I of the P3 project, a prototype GridShare was designed and built to demonstrate the ability for the technology to encourage load-shifting in two ways: by using red and green LED lights to indicate the state of the grid to the user and by preventing residents from using large appliances during brownouts. The objectives of Phase II of the P3 project are to improve upon this original prototype and test the GridShare devices in a village-scale pilot installation in Rukubji, Bhutan.

 

Rukubji, a village of approximately 90 households connected to a 40 kW micro hydro system, currently suffers from daily brownouts and serves as an excellent location to implement a pilot installation to evaluate the potential of the GridShare technology to reduce brownouts in village scale renewable energy systems (Figure 3). To perform the pilot installation, 120 GridShare devices were designed, tested and manufactured. In collaboration with the Bhutan Power Corporation and the Department of Energy of Bhutan, 89 devices were installed in June of 2011. These devices will be monitored through at least January of 2012 to determine their effectiveness, reliability and the degree of user satisfaction. If successful on this small scale, GridShare technology has the potential to increase the viability of renewable energy mini-grids in thousands of communities worldwide.

 

Figure 3. The main village of Rukubji is located in the center of Bhutan in the Himalayan Asia (L). Kyle Palmer
and Chhimi Dorji install a Gridshare on the outside of the resident Dorji Lham's house (R)

 

 

The GridShare team has been very successful in our work on Phase II. After receiving the Phase II award, we immediately started work on an initial summer field visit to the village of Rukubji in July of 2010. During the visit we held community meetings to introduce the project and demonstrate the prototype, surveyed every household and installed voltage and current loggers to monitor the electric system for the duration of the project. The surveys investigated resident’s current electricity use patterns, issues with brownouts and interest in the GridShare as a solution. Additionally, the team began to delineate the role of the Bhutan Power Corporation in the project through a subcontract and MOU, and secured the support of the community through verbal agreements with each household and a signed agreement with the village leaders.

 

Findings from this initial visit included over 96% of households reporting that they experienced brownouts once or twice a day, and all but three households stated that they could use their rice cookers at an earlier or later time to reduce the brownout problem. All households agreed to participate in the project. In addition to these findings, through investigation of the electrical system, community feedback and initial testing of the GridShare prototype, the GridShare team identified several design improvements. Some of these improvements required substantial redesign of the board and installation, which increased both the unit cost (as discussed in Section 4) as well as the timeline for the initial installation.

 

In addition to the extra time needed to address the design revisions, the timeline for the project was pushed back by 6 months to accommodate adequate quality testing for the devices and to address the suggestion of the villagers that late June would be the best time to install. Adjusting the schedule by 6 months required moving the initial installation to June of 2011, rather than January 2011, reducing the monitoring period to 6 months rather than a year, eliminating the interim evaluation trip and scheduling the final evaluation trip for January of 2012. The timeline cannot be extended as the village of Rukubji is now likely to be connected to the national grid in the spring of 2012, which would substantially affect residents’ perception of the GridShares. See Table A1, the Revised Workplan for details.

 

Despite the scheduling adjustments, the project has successfully passed many milestones. The GridShare team redesigned and tested the circuits and enclosures with a series of environmental and functional tests to ensure their ability to operate in the harsh climate of Rukubji and on the extremely variable electric grid with extreme fluctuations in both voltage and frequency. For quality control and to speed the manufacturing process, printed circuit boards (PCB) were assembled by outside companies, while student volunteers completed the final assembling and testing of each PCB in its weather-proof enclosure (See appendix for the circuit diagram, logic flowchart, and pictures of the GridShare device and breaker enclosure). After testing each GridShare, all 120 devices, along with 120 circuit breakers were shipped to Bhutan for the installation in June of 2011. In approximately 10 days, the team installed 89 GridShares on 81 houses and two local businesses (Figure 4). The GridShares which were shipped but not installed are being stored in Rukubji in case new houses are built or any existing units fail during the project period. During and after installations, the team talked with members from each household to ensure they understood how the device worked and who to contact if they had questions or problems with the device (See appendix for examples of the education materials distributed). All reported problems were resolved while the team was in the village and as of early August, no further issues have been reported. Many residents expressed their excitement for the project and stated that the LED lights were very helpful in indicating when they can reliably cook without risking spoiled rice.

 

Figure 4.  Installation diagram for Gridshares (top). BPC electrician, Sangay Phuentsho, installs a Gridshare
and breaker box (bottom left). LED box with instructional sign installed below (bottom right).

 

 

The unit cost of the final GridShare prototypes, excluding shipping, was $93.37. Thanks to generous donations and sponsorships, this cost was reduced to $56.26 per unit (Table A2). As a research project for an economics course, student team members performed a lifecycle cost analysis for a GridShare installation in comparison to four other alternative scenarios which could address the issue of brownouts in Rukubji: expansion of the microhydro system, installation of large battery banks, incorporation of a diesel generator for peak loads, and connection to the national grid (Table 1 and Table A3) (Harper, Mielke and Quetchenbach, 2010).

 

Table 1. Results of cost benefit analysis for five alternative scenarios ²

 

	Lifecycle cost	Levalized cost of increased capacity ($/kWh)	LEvelized cost of avoided CO2e ($/tCO2e)
Hydro expansion (89 kW)	$830,329	$0.379	$132.97
Batteries	$450,037	$0.228	$72.07
Diesel Generator	$268,423	$0.123	$45.32
Grid connection	$199,518	$0.032	$6.95
GridShare	$9,225	$0.005	$1.64

 

 

 

Based on the low lifecycle cost ($9225) and the cost of carbon dioxide equivalent (CO2e) reduction ($1.64/tCO2e), a GridShare installation is highly favorable. However, connection to the national grid offers a significant increase in utility over the GridShare as it would not impose a finite limit on the amount of electricity the village can consume.3 Additionally, the GridShare imposes an even greater disutility, by requiring users to change the time they cook. This inconvenience cost is difficult to quantify in economic terms, though this additional “cost” could be the determining factor as to the realistic functioning of the GridShare.

 

 

Quantifiable and qualitative benefits to people, prosperity and the planet will be assessed at the end of the pilot project and will better inform the cost-benefit analysis for a GridShare installation. At the end of the six-month monitoring period, an evaluation of the system will be conducted by the HSU team, BPC, and DOE Bhutan. In addition to billing records provided by the BPC and the data collected by the data loggers, feedback from the community will be collected through surveys. The survey will help determine the effects of GridShare technology on energy consumption, time spent on cooking, and issues with indoor air quality, along with the individual’s satisfaction with the device and their electric service.

 

 

Following the initial site visit, the team identified a number of design modifications and additional costs related to the installation that had not been considered in the original budget. As part of the agreement to work with the BPC, the team needed to procure a fire insurance plan for the village to cover potential damage from the GridShare devices. This plan was purchased through the Royal Insurance Company of Bhutan for $5265. Another significant additional cost was that of shipping the GridShare devices to Bhutan. After realizing the size (4”x4”x4”) and weight (~1 lb) of the devices, the potential of transporting the GridShares in checked luggage, as originally planned, was impractical. Shipping costs for the GridShares and circuit breakers amounted to $5782. Design improvements resulted in additional cost increases, the most notable change to the design was the inclusion of a 20 amp circuit breaker to protect the device and enable safe maintenance while the device is installed. Including a circuit breaker and a low-cost weather-proof container for the breaker added approximately $34 to the unit cost of the GridShare and doubled the shipping costs. Additional changes included upgrading to a microchip with greater processing power, using a larger relay rated for 20 amps rather than 10 amps, including circuit components able to measure and account for changes in frequency of the incoming power, and redesigning the circuit to provide a higher voltage to the board during severe brownouts (below 120 V). Additionally, last minute supply shortages due to the tsunami in Japan required some redesign of the circuit board, replacement of certain components and a slight price increase in others.

 

To account for these price increases, the team worked to minimize the development, installation and education costs while seeking additional sources of funding. The team decided, in the interest of time, money and practicality to construct 120 GridShares instead of the original 150 planned. Graduate student Tom Quetchenbach donated time and supplies for the project from his fellowship from the National Science Foundation (Award #1011464) through the Division of Graduate Education ($3000 plus many hours of labor toward the project). In addition, sponsorships from Sunstone Circuits ($500 sponsorship), Screaming Circuits ($2513.60 in discounts and sponsorships), and Industrial Electric in Arcata ($1438.80 in discounts and donations) significantly cut costs. To help reduce travel costs, Humboldt State Clubs and Activities promised a $500 grant toward the summer 2011 field visit. Further, the Schatz Energy Research Center provided financial and administrative support as well as laboratory space and machine shop services. While the team is continuing to seek outside sources of funding to support on-going work on the project, all of these donations have helped to sustain the project to this point.

 

 

Table A1. Revised Work Plan

 Apple, J., C. Dorji and M. Harper, “Trip Report: Bhutan Site Visit,” Schatz Energy Research Center, July 2010. (Available on request)

 

Bhutan Power Corporation, “About Us,” Bhutan Power Corporation Limited website, 2010, http://www.bpc.bt/about-us.

 

Dorji, K. P., “The Sustainable Management of Micro Hydropower Systems for Rural Electrification: The Case of Bhutan,” Master of Science Thesis presented to Humboldt State University, 2007.

 

Fulford, D. J., P. Mosley, and A. Gill, “Field Report: Recommendations on the Use of Micro-Hydro Power in Rural Development,” Journal of International Development, 2000. 12: 975-983.

 

Harper, M., K. Mielke and T. Quetchenbach, “Valuing the GridShare: Economic Analysis of the Grid-Share and Comparative Methods of Reducing Brownouts on Isolated Mini-Grids”, a paper submitted for Econ 550: Economics of Energy and Climate Policy, November 18, 2010. (Available on request).

Quetchenbach, T., “Implementation of a Low-Cost Smart Grid Device to Prevent Brownouts in Village Micro-Hydro Systems,” a project presented to the faculty of Humboldt State University in partial fulfillment of the requirements for the degree Master of Science in Environmental Systems: Environmental Resources Engineering Option, August, 2011. (Available soon at http://humboldt-dspace.calstate.edu/xmlui/handle/2148/537)

 

Smith, N., “Low Cost Electricity Installation,” Intermediate Technology Consultants report for the Overseas Development Administration, 1995.