Wednesday, July 22, 2009

Our aging electric grid

Electric power generation is biggest source of lost energy in absolute terms. Only 31% of the energy used to generate electricity ends up as distributed energy. When line losses, transfer stations, and the inefficiencies of the appliances and factories that use electricity are added, useable energy can drop as low as 2 percent.

Electricity represents a growing portion of total energy use. It is expected that electricity will constitute 16 percent of the total energy consumption in 2009 as compared to 9 percent about 20 years ago. While transportation accounts for 20% of our total greenhouse gas emissions, the electrical system accounts for 40%. But our transmission system is badly out of date; its infrastructure will need a huge investment to meet the expected future demand. According to The Brattle Group, a $1.5 trillion investment will be required between 2010 and 2030 to pay for new infrastructure.

The Department of Energy estimates that demand for electricity has increased by around 25 percent since 1990 while construction of transmission facilities dropped 30 percent. The resulting congestion has raised line losses, which have increased from a low as 5 percent of electricity transmitted in 1970 to 9.5 percent by 2001. This represents roughly and additional 3 quadrillion Btus lost to inefficiency.

Our aging electric infrastructure is one major reason why plans for a smart grid have been getting a lot of attention as the most efficient alternative to this problem. A smart grid would require less new capacity by saving more energy.

Smart grid technologies would transform the grid from a centralized, producer controlled network to a less-centralized, more consumer interactive network. Adding digital sensors and remote controls to the transmission and distribution system would improve efficient transmission of electricity. It would be able to cope with new sources of renewable power, allow for coordinated charging of electric cars, provide information to consumers about their usage and allow utilities to monitor and control their networks more effectively.

An important part of the smart grid would be smart meters that would give consumers real time price and usage information and allow them to make better decisions about when they use appliances. Studies have found that people using smart meters reduce their usage by about 7%. With added incentives people curtail their usage during peak demand by 15% or more. Eventually smart meters could automatically start appliances when demand and price are the lowest.

The Department of Energy claims that, while some of the technologies required for a smart grid can be deployed in the near future, a true smart grid is generally considered to be a decade or more away. Still, a few areas have gone ahead with a transition to a smart grid. A DOE demonstration project on Washington’s Olympic Peninsula set up a system that responded to simple instructions set in place by consumers in their preference profiles. Energy was managed on the consumers’ behalf to save money and reduce the impact on the grid. Consumers saved around 10% on their bills while peak load was reduced by 15%.

The European Union has an even more aggressive smart grid agenda, a major component of which includes having buildings function as power plants. However the EU has an advantage that it does not have as large and antiquated a legacy system as the US and therefore upgrading the grid has been easier.

In some cases the most efficient use of energy comes from going off the grid entirely. The USA Today reported that there were around 180,000 families living off-grid, a figure that had grown at a 33% a year rate for a decade. In 2002, Woking Borough Council in England adopted a new Climate Change Strategy that involved replacing the national grid with a local one using combined heat and power, fuel cells, renewable energy, and private wire systems. By 2009, the Council had delivered over 20 different Combined Heat and Power and photovoltaic projects, and was offering the service to private citizens of the Borough. In 2006, CO2 emissions had been reduced by 81% in the Council's property, with a 21% reduction in CO2 emissions achieved Borough-wide. Electricity consumption was down nearly 50% in areas covered by the local grid.

are a halfway measure between being total reliance on the grid, and going completely off grid. Micro-grids are self sufficient grids that remain hooked into the larger national grid. Micro-grids can be run using whatever fuels are available and dependable in a local area. If the micro-grids produce more power than they need, they could sell it to the national grid at a profit. They would also be suitable to adopt renewable energy sources because the investment and conversion time would be smaller. Micro-grid networks would be modular, so if one failed others would stay in service, reducing the chance for region-wide outages. If the regional grid failed, each micro-grid could continue to function. Micro-grids would also be well suited to the use of cogeneration systems, adding to their efficiency.