Cristina Inês Camus

Micro-generation evaluation of the zero emissions technologies in the Portuguese market

Micro-generation is the small scale production of heat and/or electricity from a low carbon source and can be a powerful driver for carbon reduction, behavior change, security of supply and economic value. The energy conversion technologies can include photovoltaic panels, micro combined heat and power, micro wind, heat pumps, solar thermal systems, fuel cells and micro hydro schemes. In this paper, a small research of the availability of the conversion apparatus and the prices for the micro wind turbines and photovoltaic systems is made and a comparison between these two technologies is performed in terms of the availability of the resource and costs. An analysis of the new legal framework published in Portugal is done to realize if the incentives to individualspsila investment in sustainable and local energy production is worth for their point of view. An economic evaluation for these alternatives, accounting with the governmentpsilas incentives should lead, in most cases, into attractive return rates for the investment. Apart from the attractiveness of the investment there are though other aspects that should be taken into account and those are the benefits that these choices have to us all. The idea is that micro-generation will not only make a significant direct contribution to carbon reduction targets, it will also trigger a multiplier effect in behavior change by engaging hearts and minds, and providing more efficient use of energy by householders. The diversified profile of power generation by micro-generators, both in terms of location and timing, should reduce the impact of intermittency or plant failures with significant gains for security of supply.

Impacts of electric vehicles' charging strategies in the electricity prices

Electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs), which obtain their fuel from the grid by charging a battery, are set to be introduced into the mass market and expected to contribute to oil consumption reduction. In this research, scenarios for 2020 EVs penetration and charging profiles are studied integrated with different hypotheses of power sources expected in electricity generation for year 2020. Simulations of the impacts in load profiles and spot prices are obtained for the Portuguese case study as well as the emissions balance between the transportation and the electricity generation sectors. Simulations made for year 2020 in a scenario of low hydro production and high costs, estimate that the price could reach the 17 cents/kWh (including wholesale, plus the net access, plus retailer revenue) for a 2 Million EVs charging mainly at peak hours. In an off-peak recharge the price reduces to about 7 cents/kWh. In a high hydro production and low wholesale prices, an off peak recharge could reach 5.6 cents/kWh. Reductions in primary energy consumption, fossil fuels use and CO2 emissions of 4%, 12% and 9% respectively were verified from the transportation and electricity generation sectors together when compared with a Business as usual (BAU) scenario without EVs and the same electricity production mix. In these extreme cases, EV energy prices were between 0.9€ to 2.8€ per 100 km.

Electric vehicles as a mean to reduce, energy, emissions and electricity costs

Electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs), which obtain their fuel from the grid by charging a battery, are set to be introduced into the mass market and expected to contribute to oil consumption reduction. This research is concerned with studying the potential impacts on the electric utilities of large-scale adoption of plug-in electric vehicles from the perspective of electricity demand, fossil fuels use, CO2 emissions and energy costs. Simulations were applied to the Portuguese case study in order to analyze what would be the optimal recharge profile and EV penetration in an energy-oriented, an emissions-oriented and a cost-oriented objective. The objectives considered were: The leveling of load profiles, minimization of daily emissions and minimization of daily wholesale costs. Almost all solutions point to an off-peak recharge and a 50% reduction in daily wholesale costs can be verified from a peak recharge scenario to an off-peak recharge for a 2 million EVs in 2020. A 15% improvement in the daily total wholesale costs can be verified in the costs minimization objective when compared with the off-peak scenario result.

Residential PV systems with battery backup power attained already grid parity

Due to the demise of FiT, PV grid connected systems focused towards self-consumption. A residential customer installing a grid-connected PV system, usually called a “prosumer”, is paid for the exported electricity less than 5 c€/kWh (or nothing) by the electricity provider while charged about 16/17c€/kWh for the same kWh. At this exchange rate it is more economical to consume than to export. Residential consumption does not coincide with PV production and the majority of the energy produced will be exported to the grid instead of self-consumed. NPV maximizes at a 95% of self-consumption in the best case studies which usually is attained with small percentage of self-sufficiency and low power installed. With further increase of retail electricity prices and decrease of PV costs the business case for storage becomes economically viable for residential customers with the advantage of increasing self-sufficiency and energy efficiency (energy is generated locally).

Short-term value for the water stored in head-sensitivity power system reservoirs

As it is well known, competitive electricity markets require new computing tools for generation companies to enhance the management of its resources. The economic value of the water stored in a power system reservoir is crucial information for enhancing the management of the reservoirs. This paper proposes a practical deterministic approach for computing the short-term economic value of the water stored in a power system reservoir, emphasizing the need to considerer water stored as a scarce resource with a short-term economic value. The paper addresses a problem concerning reservoirs with small storage capacities, i.e., the reservoirs considered as head-sensitivity. More precisely, the respective hydro plant is head-dependent and a pure linear approach is unable to capture such consideration. The paper presents a case study supported by the proposed practical deterministic approach and applied on a real multi-reservoir power system with three cascaded reservoirs, considering as input data forecasts for the electric energy price and for the natural inflow into the reservoirs over the schedule time horizon. The paper presents various water schedules due to different final stored water volume conditions on the reservoirs. Also, it presents the respective economic value of the water for the reservoirs at different stored water volume conditions.

Integration of Electric Vehicles in the Electric Utility Systems

In the last decades, the energy use for electricity production and for the transportation sector have more than duplicated (IEA WEO, 2007) and today face a number of challenges related to reliability, security and environmental sustainability. The scientific evidence on climate change (IPCC, 2007) has been calling for urgent cross-sector emission cutting and electrified transportation is in the portfolio of the technology options that may help to solve the problem (IEA ETP, 2008). In most of OCDE countries the transportation and electric power systems contribute to the majority of CO2 emissions (IEA WEO, 2008) and most of the fossil fuels (coal, natural gas and oil) used to produce electricity and for transportation are, in many of these countries, imported. Oil accounts to the majority of this primary energy imports and more than 60% of it, is used for transportation (mainly road transportation) and so is responsible for the majority of emissions associated to the transport sector. All these facts are pressing decision makers/manufacturers to act on the road transportation sector, introducing more efficient vehicles on the market and diversifying the energy sources. The technological evolution of the Electric Drive Vehicles (EDV) of different types: Hybrid Vehicles (HEV), Battery Electric Vehicles (BEV) and Fuel Cell Vehicles (FCV), will lead to a progressive penetration of EDV s in the transportation sector taking the place of Internal Combustion Engine Vehicles (ICEV). The next step in EDV technological development, already announced by some of the main automakers, (EV World, 2009) is the possibility of plugging into a standard electric power outlet so that they can charge batteries with electric energy from the grid. A lot of companies including many key and niche players worldwide are reported to have been developing models for the coming years in the segments of battery powered electric vehicles, Plug-In Hybrid Electric Vehicles (PHEVs), and fuel cell electric vehicles (EV ReportLinker, 2007). By shifting currently non-electric loads to the grid, electric vehicles might play a crucial role in the integration of these two critical elements of the whole energy system: power generation and transportation. In a scenario where a commitment is made to reduce emissions from power generation, the build-up of new intermittent power capacity is problematic for the electric systems operation (Skea, J, et al., 2008) and usually needs large investments in energy storage. The addition of extra load from electric vehicles in the electricity system can be challenging, if together both systems are more efficient and able to reduce overall emissions. Furthermore, for future energy systems, with a high electrification of transportation, Vehicle to Grid (V2G) concepts can offer a potential storage capacity and use stored energy in