Group items tagged

Canada, home to about 475 hydroelectric plants with a capacity of 70,000 MW, produces about 355 terawatt-hours of hydropower each year. But Canada's untapped potential is far greater. According to a study commissioned by the Canadian Hydropower Association, Canada has 163,000 MW of untapped hydropower potential, more than twice the country's existing hydropower capacity.

In the latest Electric Power Research Institute Journal, an article titled "Hydropower Reservoirs: A Question of Emissions" notes that reservoirs used for hydropower and for pumped-hydro energy storage are not necessarily as green as you might imagine. Or rather, they might be too green: carbon-rich organic material that accumulates on the reservoir floor can be the source of carbon emissions. A recent study of the 90-year-old Lake Wohlen, in Switzerland, for example, found high emissions of methane, as recently reported in the journal Environmental Science and Technology, in an article titled: "Extreme Methane Emissions from a Swiss Hydropower Reservoir: Contribution from Bubbling Sediments."

We have produced a report and map showing the hydropower opportunities in England and Wales and the environmental sensitivities associated with exploiting them.

Production of small SHP improves in the country

The JRC has published a study mapping the potential of renewable energy sources in Africa. The report analyses the continent's current energy consumption and assesses potential of renewable energy sources - solar, wind, biomass and hydropower - and their cost efficiency and environmental sustainability.

This is why Highview has been testing its 300-kilowatt pilot plant for the past nine months, supplying electricity to the UK's National Grid. The process stores excess energy at times of low demand by using it to cool air to around -190 °C. Excess electricity powers refrigerators that chill the air, and the resulting liquid air, or cryogen, is then stored in a tank at ambient pressure (1 bar). When electricity is needed, the cryogen is subjected to a pressure of 70 bars and warmed in a heat exchanger. This produces a high-pressure gas that drives a turbine to generate electricity. The cold air emerging from the turbine is captured and reused to make more cryogen. Using ambient heat to warm it, the process recovers around 50 per cent of the electricity that is fed in, says Highview's chief executive Gareth Brett. The efficiency rises to around 70 per cent if you harness waste heat from a nearby industrial or power plant to heat the cryogen to a higher than ambient temperature, which increases the turbine's force, he says. Unlike pumped-storage hydropower, which requires large reservoirs, the cryogen plants can be located anywhere, says Brett. Batteries under development in Japan have efficiencies of around 80 to 90 per cent, but cost around $4000 per kilowatt of generating capacity. Cryogenic storage would cost just $1000 per kilowatt because it requires fewer expensive materials, claims Brett.

n 2010, thermal energy displaced hydro as the major source of energy generation for the Chilean Central Interconnected System.  Coal, natural gas, and diesel supplied over 50% of energy consumed while hydropower accounted for 48%.  This trend is expected to continue in 2011 if current water shortage conditions persist. (El Mercurio, 1/4/11)  Last year’s drought created a 26% increase in thermal generation as compared to 2009.

The Regional Energy Efficiency Strategy initiative led by Bun-ca has reported an energy savings of 9368 MWh over the past six years, equivalent to 4992 tons of carbon dioxide, by working with 190 companies in the industrial and commercial sectors to become more energy efficient.   Recently UNEP’s En.lighten study estimated that Costa Rica could save 276,000 MWh and $27.6 million per year if they changed all light bulbs to CFLs.  The cost of this change was estimated to be $22.63 million.  (El Financiero CR, 1/3/11)

The Mexican government is planning to invest four billion dollars to build a one thousand megawatt renewable energy storage facility in Northern Mexico.   The facility will use a special kind of sodium sulfide batteries for the project which is expected to be completed in the next six years.  (Clean Techies, 1/6/11)

The renewable energy super-grid is planned to become operational in 2020 and will involve Europe's leading utilities, who will share part of the massive price tag.   The project would be the first multinational grid designed to address the fluctuating nature of green power generation, one of the main challenges slowing down the share of renewables in the baseload energy mix.   Energy from power produced from the wind farms at night could be stored in Norway's hydropower facilities to be released the following day; helping to secure a more stable energy supply.