For households, energy efficiency represents one of the most effective ways to reduce energy bills, with typical savings of 20 to 30% for an affordable portfolio of energy saving measures, and over 50% for deep energy retrofits.
Energy efficiency also represents a lucrative business investment, with higher returns and lower risks than conventional investments.
For energy utilities, energy efficiency represents the cheapest energy resource available, easily outcompeting coal, natural gas, wind and solar in terms of the cost per megawatt-hour delivered.
For governments, energy efficiency increases industrial competitiveness, improves energy security and represents one of the largest and cheapest greenhouse gas abatement opportunities.
However despite the clear benefits of energy efficiency, we still waste a tremendous amount of energy in homes and businesses, leading to what academics term the 'energy efficiency gap'
One of the key challenges in energy efficiency is that there is such a wide range of options. You could replace your old light bulbs with modern LEDs, insulate your ceiling, replace your old fridge, or install solar panels. Or you could replace your heating system, put blinds on your windows, or draught-proof your doors and windows.
Each of these energy saving options performs quite differently in different situations. For instance, an LED lighting upgrade has a strong case if you currently have a large number of incandescent or halogen lamps, but won't perform as well where you already have CFL lighting or where lights aren't switched on very often. Similarly, an insulation upgrade will perform quite well for sealed buildings in cooler climates but offer less benefit to cross-ventilated buildings in warmer climates.
There is also a natural priority to energy efficiency investments. For instance it doesn't make much sense to install insulation if you haven't already draft-proofed your doors and windows. And it doesn't make much sense to install solar panels on your roof if you haven't eliminated unnecessary electricity consumption. This priority is often unclear to households, and isn't helped by companies pushing a specific solution.
To make matters worse, there are a wide range of suppliers of each of these products and services. Finding a quality supplier can require a great deal of homework and often involves obtaining a range of competitive quotes, negotiating a contract and securing rebates and/or finance.
Households have been understandably overwhelmed by the whole process and have been captured in a situation where their energy bills are rising but they don't know what to do about it.
And households aren't alone.
Commercial businesses still waste a dramatic amount of energy and money on poorly specified and operated heating, cooling, and lighting systems. Many of the fixes require a simple tune up and quite inexpensive equipment but once again assessing the range of options out there is overwhelming to the average small business.
For similar reasons, energy utilities have continued to under-invest in energy efficiency and over-invest in new infrastructure, leading to billions of dollars of unnecessary expense, and ultimately increased energy bills for consumers.
Solar photovoltaic generation (or solar PV) has emerged in recent years as a key tool for reducing our dependence on fossil fuels.
Although it was once prohibitively expensive, solar PV has achieved a breakthrough in cost reductions this past decade, with installed costs reducing by more than half.
The upshot of this cost breakthrough is that solar PV now represents the cheapest energy available 'at the plug' for a vast number of households and businesses.
An inflexion in solar PV uptake is therefore occurring around the world, driven by unstoppable market forces and a strong consumer desire for independence from dirty and increasingly expensive fossil fuel generation.
Solar PV requires detailed site-specific design to ensure the system delivers maximum value to the customer.
For instance, the cost per kilowatt of a solar PV system reduces with increasing size owing to economies of scale in production, distribution and installation. However in most areas the rate you receive for exported electricity is lower than the rate you pay to purchase it from the grid. This means the bill savings per kilowatt-hour of electricity generated reduce with increasing system capacity. An optimal system size therefore occurs where the reduced installed costs per kilowatt of capacity are overcome by reduced bill savings per kilowatt-hour generated.
The optimal PV system size is unique to each property and is determined by the interaction of a wide range of factors including your locally available sunshine, the installed cost per kilowatt of different system capacities, your local electricity rate structure, and your unique electricity consumption profile through the day.
Solar installers usually combine electricity bill information with rules of thumb to size solar PV systems but these approaches don't take into account fluctuations in electricity consumption and generation throughout the day, and how these fluctuations impact time-of-use and feed-in tariffs.
Another key challenge in the solar PV market is market coordination. According to recently published research by the US National Renewable Energy Laboratory, solar retailers and installers spend on average $0.4 per watt on customer acquisition costs. This translates to $1,200 of the cost of an average residential solar PV installation.
We think solar installers would much rather spend their time installing solar systems than chasing customers. We also think that we can accelerate the uptake of solar PV by reducing these so-called 'soft costs' of solar PV.