Reduced Vulnerability

A central power system based on extensive T&D is vulnerable to human and natural threats. Two specific threats to electricity networks are extreme weather and terrorism. Wider DE implementation reduces this vulnerability to damage or destruction and it is now commonly recognized that a more dispersed generation system creates diversity, resulting in a more robust and reliable electricity system.

In 1998, an ice storm hit Canada and the USA. The 100 millimeters of freezing rain destroyed 1000 high voltage transmission towers and some 30,000 distribution poles leaving 1.63 million people without power. One month after the storm, electricity was still not restored for 700,000 people and costs for Montreal and Ottawa alone were around $500 million. In 2003 a blackout caused by a falling branch plunged more than 50 million people into darkness (1in 3 Canadians and 1 in 7 Americans). Total financial losses arising from the disaster have been estimated in the order of $6 billion USD. A similar episode in Italy the following month cut off power to the entire country of Italy (some 56 million people). There is considerable evidence that increased DE distributed thorughout a grid can go a long way to reducing an areas vulnerability to power outages. Similarly, a 2001 study following the 11 September attacks suggested that a system based more on gas-fired distributed generation plants may be five times less sensitive to systematic attack than a central power system.

As societies become more and more dependent on electricity for the economy to run individuals and industries alike are becoming increasingly wary of the dangers of blackouts. Many are losing confidence in the ability of traditional power supply to provide sufficient quality and are turning to DE, which can provide relief for congested high peak demand T&D lines and so reduce the risk of rolling brown-outs or voltage fluctuations.

Increased Self-sufficiency

Closely related to reduced vulnerability, the increased self-sufficiency that DE provides is still a distinct benefit. Generating power onsite can reduce the dependence of homes and businesses on imported energy. Especially for larger installations DE can increase the bargaining power of factories or communities with energy providers such as utilities and fuel suppliers. On a larger scale communities or regions that use a large proportion of DE will be less reliant on energy imports to drive the economy. The positive results arise both from the increased efficiency that DE offers and the increased proportion of renewables which are a natural fit with DE.

The city of Malmö, the commercial centre of southern Sweden, has achieved a high level of self-sufficiency through a diverse approach to energy generation in the city. Energy technologies applied include solar/PV, wind, geothermal, biomass CHP etc. The energy sources are largely connected and integrated in the buildings, which are in turn connected to the district heating network and therefore benefit the surrounding community ensuring constant supply of heat and electricity. As a result of the focus on DE investment the community is largely energy self sufficient requiring few imports.