Calgary Home Features the Potential for Distributed Generation

Gary Holden believes he has the first true cogeneration house in Canada and perhaps North America.  His Calgary home features a new Stirling gas engine, which takes the waste heat from his space-heating boiler and produces enough overnight electricity, in winter, to power seven plug-in hybrid electric cars - something he thinks will be on our roads in only a few years.

Now, you might expect this type of pioneering initiative from an environmental zealot far removed from the mainstream.  But when it's the president and CEO of a major Alberta utility, Enmax Corporation, it suddenly doesn't seem such a distant dream.  "Having Stirling engines in homes is really leading-edge technology, but it's starting to take off in Europe and should work well in any climate with a long heating season," says Holden.

Indeed, Holden's home installation is a pilot project for what he hopes will soon be a widespread program to bring distributed-generation energy to the masses in Alberta.  Stirling engines are one of about four alternative technologies - solar photovoltaic (PV) cells, solar hot water systems and micro wind turbines are the others - that Enmax envisions offering to interested residential customers if current pilot projects prove feasible.

"Customers would be able to pick one or more of these technologies, and we would install them," says Holden.  Customers would pay some of the capital cost plus a monthly rental fee of about $40 to $60. 

One step that will bring this distributed generation future closer to reality is a provincial regulation - effective January 1, 2009 - making it considerably easier for small renewable energy installations to be connected to the electric grid.  These micro-generating plants, producing less than one megawatt of power, can be powered by such sources as solar, wind, small-scale hydro, biomass and fuel cells.

"To have widespread use of technologies like solar electric or Stirling engines, you need to have smart, bidirectional meters, which allows you to sell your surplus electricity to the grid," says Holden.  "Most new technologies take about 10 years to become ubiquitous."

It remains to be seen how common distributed-generation systems will become in Alberta over the next decade.  Those powered by small run-of-river or biomass projects will be somewhat curtailed by higher capital costs and the proximity to their raw sources of energy, though biomass could certainly help power a number of farm operations.

Some proponents estimate wind could provide 20 per cent of Canada's and the United States' electricity by the mid-2020s, though the vast majority of this will undoubtedly come from big wind farms.  Because of municipal regulations tied to concerns about their current size and noise, residential wind turbines in Alberta will likely be largely restricted to farms and acreages for the foreseeable future.

Similar forecasts call for solar energy to supply more than 10 per cent of North America's electricity within the next two decades.  Distributed generation could play a considerable role here, given the broad distribution of sunshine and the ability to easily install solar panels on the rooftops of homes and businesses.

"My speculation is we could see a pretty significant conversion of low-rise commercial buildings with flat roofs to solar farms," says Holden.  "From my office window (in south-central Calgary), I can see 50 to 100 two-storey buildings with flat roofs.  If you cover them with solar hot water or solar PV cells, you could take a huge cut out of their (grid-supplied) energy use."

The widespread adoption of technologies like solar-powered electricity will largely depend on a continued drop in their installation costs and on government regulations promoting their use.  California, for example, is offering some $3 billion in incentives to create 3,000 megawatts of new solar electricity by 2016.  Other jurisdictions, like Germany and Ontario, have provided small distributed-generation projects with generous incentives such as the ability to sell surplus electricity to the grid at prices well above market rates.

To date, this approach has not been followed in Alberta, where the emphasis has been on a largely deregulated, unsubsidized energy market.  Some renewable energy advocates, however, say a truly level-playing field would take into account the societal pollution costs of energy derived from fossil fuels.  Holden, for one, says if the Alberta government can funnel $2 billion-plus into carbon capture and sequestration, it should also consider priming the renewable energies pump to help get people over the capital cost hump.  In its new energy strategy, the provincial government notes, though, that the rising cost of making coal-fired generation cleaner - which includes such technologies as gasification and carbon capture and sequestration - will make renewable energies more competititve.

In the meantime, several emerging technologies should help improve the long-term viability of distributed generation systems.  A considerable drawback to renewable energies such as wind and solar power is their variability - that is, no power is produced when the wind isn't blowing or the sun isn't shining - coupled with the difficulty of storing their surplus energy when they are producing.  But as options such as pumped hydro, compressed air and advanced chemical batteries and fuel cells are further developed, it should become more economical to store that surplus power.  A new generation of small, efficient gas turbines should also be able to provide nearby backup power to variable renewable energy sources.  Finally, microturbines and fuel cells could be turned on and off as needed to provide another local source of combined heat and power.

Some foreign utilities with large, variable wind supplies are already balancing power supply and demand by interconnecting grid systems over large areas, employing hydroelectric reservoirs for temporary storage and using gas turbines to meet peak power demand.  Smart grids also have a role to play, using advanced electronics technologies to help finely balance the demand and supply of diverse electricity sources, including variable renewable energies such as wind and solar.

"With smart grids, you can detect problems with lines and efficiently reroute power, so there's the least amount of disruption for the customer," says Nguyen Tran, director of customer operations with FortisAlberta, which distributes electricity to many Alberta homes and businesses.