The Renewable Energy (RE) sector worldwide is in its infancy in terms of market size but offers immense commercial potential, especially at the local level. In the UK, the market sprang into life when taxpayer subsidies for grid-tied installations were implemented in April 2010. The grid-tied sector relied on subsidies which have created market distortions and an unstable, artificial market. However, some of the technology initially developed for grid-tied RE markets, and some developed specifically for off-grid applications, has now reached a level of maturity that can offer reliable, fuel free power systems, which do not need subsidies to remain effective for the user, and represent an international market.
Off-grid renewable power has been neglected in regions where feed-in tariff grants have made on-grid solutions (power worth <£0.10/unit being “bought” for £0.24/unit) irresistibly attractive at first sight. However, off-grid power can be worth as much or more in many applications, as the alternatives either carry hidden operating costs or involve an initial capital investment which is prohibitive. Off-grid power applications, for many years the exclusive domain of portable, fossil fuel generators, are now being scrutinised by users who are keen to reduce energy costs, noise, pollution, meet carbon reduction mandates and solve humanitarian problems.
In the tropical and sub-tropical latitudes of the World, generating power from a single source of RE can provide reliable off-grid power. However, everywhere else presents a different picture, and hybrid systems using multiple sources of RE take centre stage.
Increasingly, security systems are moving towards ever greater integration of sensors using a range of communications technologies. Systems are required to provide ever better quality and greater quantities of data from sensors placed in remote and/or unattended sites. Power demands have been a lesser priority than security system performance. However, significant reductions in power demands have resulted from the use of lower power electronics, for example LEDs, and this has opened the door to off-grid power from renewable sources.
Off-grid power is a very different engineering proposition from its grid-tied, subsidised cousin.
Grid-tied systems usually have a sole source of RE which is connected via an inverter directly into the main grid.
Value of hybrid systems
Off-grid usually uses multiple sources of RE energy to provide resilience, and each source has its own characteristics. In addition, off-grid systems require power storage, power management and distribution, all of which must be balanced and integrated between themselves and with the applications. To deliver the performance required by the customer, a system integration approach is essential. A critical element in an effective off-grid system is the power storage. There is now a wide range of technologies, offering physical sizes, weights, power densities and costs to meet practically any demand, whether for a few hours or 50 years. Accurately specifying this element is vital for an effective system. RE sources now include wind, solar, hydro, fuel cells, and other newer technologies. Technical and performance developments to some of these are moving forward with impressive speed, assisting the search for increased system performance.
Economies from power management
The introduction of RE power is showing the importance of how power demands can be managed. Slicing loads reveals valuable opportunities to manage existing power plant more effectively, not least by increasing the periods when it is working at, or closer to, optimum performance, with the commensurate reductions to fuel consumption and maintenance. A RE power system can provide intelligent power management, load levelling, UPS and primary power.
Off-grid power investment is made because the owner/user wants the power. Conversely, grid-tied investment is a financial decision. The power generated is neither seen nor used by the system owner. The value of power where there is none is an altogether different equation from where reliable power is available. Similarly, where only intermittent power is available - as with most of urban Africa, Asia, South America, and some US mainland States - having reliable power every day, instead of a working or school day of 3 to 4 hours, is hugely valuable.
In the UK, the cost of bringing mains grid power even quite short distances can be prohibitively costly, for example across an urban street, let alone 500 metres.
For security system integrators, off-grid RE can be something of a mystery. There can be an understandable perception of fragile equipment drawing intermittent energy out of the sky, wind or river, and somehow delivering reliable and consistent electricity of the quality required by modern sensors and other technologies; perhaps too ephemeral to be credible.
Changing this perspective can be easier when it is understood to what extent the UK Ministry of Defence (MoD) is investing in RE and other Eco-Commercial technologies to reduce their energy requirement and improve operational effectiveness. In this respect, they lead civilian markets by about 18 months
MoD has mandated emission reduction targets and post SDSR, are caught between budget reductions and fossil fuel cost increases. It is worth noting that research completed for the US Department of Defense revealed the Fully Burdened Cost of Fuel for their campaign in Iraq was USD400 per gallon; that is a US gallon of 4 litres. MoD conducted similar research for the Afghanistan theatre of operations, and although the FBCE cost was less, it was still eye-popping.
For several years, MoD have been engaging with the Eco-Commercial sector. This encompasses a range of energy reducing technologies, including electricity and heat generation and distribution, water and waste management, and lower power electronics components.
For both Civilian commercial and Military systems, the new design engineering paradigm can no longer be predicated on the availability of near-limitless, low cost power. The priority must be to design out power requirements, and from a RE perspective, use 12vDC as much as possible; in a way, back to the future.
The RE sector as a whole is developing swiftly from a few, disparate and almost entirely small, innovative suppliers, historically with incoherent markets and confused buyers, to the situation where many of whom now can see the potential that RE holds in reducing costs and increasing reliability of supply.
The key to effective off-grid RE deployment is to generate the power close to the point of consumption, and usually to keep it significantly smaller than Utility scale. For Military Operational Areas, this means portability and mobility are vital. System reliability and performance optimisation demand much of the system engineering, and new technologies and low power electronics are assisting this drive. Smaller scale RE systems now provide a realistic alternative to traditional fossil fuel generators with their attendant logistics, maintenance and reliability costs.
Unattended or silent watch power requirements include town centre, critical infrastructure, border surveillance, storage containers, highway signs, military reconnaissance and intelligence gathering, mobile catering facilities and mobile telecommunications base stations, with others becoming evident as the application of RE becomes more widely understood. Remote monitoring technologies can provide even more effective system management, enabling in-theatre military commanders to plan operations taking power availability into account.
Even if the delivery cost of energy to most security systems is not in the extremes of the Military Operations, the price of crude oil is an inescapable driver of RE value.
Off-grid RE has another interesting perspective relating to the cost of energy. To compare fossil fuel derived power with RE power on a like for like basis, the through-life cost of a generator must be considered over 20 years, the typical RE system life. For some RE systems, this can be extended to 30 years or more. Similarly, power storage technologies have developed and long life batteries can be used unattended for five or ten years.
As the costs of fossil fuel has risen, and RE components and the balance of systems have declined in the last 5 years, returns on investment (RoI) have improved greatly. There are too many factors involved to give a widely applicable RoI but an integrated, correctly engineered system which is used constantly can provide an acceptable RoI, excluding carbon credits and the value attached to the tick in ‘the green box’.
[Editor's notes:
Colin Sworder is Managing Director of Kraft Maus Ltd, off-grid renewable energy systems integration specialists who design, build and supply systems to provide power where there is none, intermittent power supply solutions, enhanced power management, and custom renewable solutions, for military, commercial and industrial markets.
This article was first published on info4SECURITY in February 2012.]
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